From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 9A3B6B7B68 for ; Tue, 6 Oct 2009 09:37:37 +1100 (EST) Subject: Re: [PATCH 0/6] PowerPc 8xx TLB/MMU fixes From: Benjamin Herrenschmidt To: Joakim Tjernlund In-Reply-To: References: <1254744999-3158-1-git-send-email-Joakim.Tjernlund@transmode.se> <20091005220420.GA27923@compile2.chatsunix.int.mrv.com> Content-Type: text/plain; charset="UTF-8" Date: Tue, 06 Oct 2009 09:37:28 +1100 Message-Id: <1254782248.7122.49.camel@pasglop> Mime-Version: 1.0 Cc: Scott Wood , "linuxppc-dev@ozlabs.org" , Rex Feany List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 2009-10-06 at 00:31 +0200, Joakim Tjernlund wrote: > > regs or regs->nip is NULL? Either one does not make sense > In any case it might be a secondary problem as DAR is NULL already > when you > enter the page fault. > > > > insn = *((unsigned long *)regs->nip); > > c000e110: 80 a9 00 00 lwz r5,0(r9) > > > > fails. > > hmm, I wonder if you managed to invalidate the a kernel TLB? > Are you using pinned kernel TLBs? You should not dereference a user address like that. Use get_user ! Obviously you got 0 in SRR0 for some reason (somebody tried to jump to 0, either intentionally or as a result of some other problem) and the above will crash the kernel when it happens. Cheers, Ben.